Conventional hopper car outlet gate arrangements have included a frame which is fastened to the underside of the hopper car. The frame encloses a door slide or gate slide which is permitted to slide horizontally in the frame between the open and closed positions. A rack and pinion or other mechanical means is employed to gain a mechanical advantage in sliding the gate slide between the open and closed postions. The gate slide itself has ordinarily been formed from steel. The gate is, therefore, usually quite heavy and prone to corrosion. Furthermore, the weight of the material within the hopper car tends to press against the gate slide with great force. The gate slide has ordinarily been supported within the frame by the use of rollers or metal slide rails. Resilient seals have often been employed to seal the gate tightly in its closed position and prevent the unintentional discharge of materials through the gate. The gate slide is usually held firmly in its closed position by the use of gravity actuated locking dogs.
One of the problems with the prior art is that corrosion of the metal gate slide, or corrosion of the metal rollers supporting the gate slide, prevents the gate slide from opening or closing smoothly. Some gates have used bushings or linings made of a low friction material such as Teflon (trade mark) in place of rollers in order to avoid the problems associated with corrosion. These low friction bushings or linings, however, tend to wear out quickly and tend to be difficult to replace. Another problem with the prior art relates to the locking mechanisms employed. The locking mechanisms tend to corrode and jam. Yet another problem with the prior art is that the sealing mechanism used tends to be inefficient and difficult to repair. The present invention contemplates an improved slide gate which overcomes all of the above problems.